An example of the lancing device utilizes a cam mechanism for sticking a lancet into skin (refer to JP-U-64-42010, for example). As shown in FIGS. 15A-15C, the lancing device disclosed in JP-U-64-42010 includes a cam 90 whose rotation is transformed into a reciprocal movement of a lancet supporting portion 91, so that a lancet 92 is moved together with the lancet supporting portion 91 to puncture the skin.
As shown in FIG. 15A, in a standby position of the lancing device 9, the cam 90 is fixed with an urged coil spring 93. A pivot lever 94 is operated to disengage the fixation of the cam 90, as shown in FIGS. 15B and 15C. Then, the cam 90 rotates about a shaft 95. The cam 90 is formed with a v-shaped groove 96, and the groove 96 engages an engaging pin 97 that is formed integral with the lancet supporting portion 91. Thus, when the cam 90 rotates, the engaging pin 97 moves along the groove 96. In this way, the lancet supporting portion 91 reciprocally moves in the puncturing direction N1 and the retreating direction N2 as guided within a sliding hole 98, whereby the lancet 92 reciprocally moves in the puncturing and retreating directions N1, N2 together with the lancet supporting portion 91.
In the lancing device 9, the reciprocal movement of the lancet supporting portion 91 (lancet 92) on puncture operation is stopped by the engaging pin 97 that is brought into contact with the end of the groove 96. Specifically, the engaging pin 97 is moved relative to the groove 96 by the cam 90 that moves due to the restoring force of the coil spring 93. Then, the engaging pin 97 collides against the end of the groove 96 when the cam 90 comes to stop. Therefore, on puncturing, the impact due to the collision of the engaging pin 97 and the end of the groove 96 is transmitted to the skin, and the impact causes pain and discomfort, and thus increase pain on sampling. Further, impact noise due to the collision may intensify the feeling of pain, and combination of the impact noise and the pain may increase discomfort.